Hydraulic remote-control system



Aug. 18, 1953 w. A. STEWART 2,649,173

HYDRAULIC REMOTE-CONTROL SYSTEM Filed May 25, 1951 s Sheets-Sheet 1 I E 1 702 A 227: re it Aug. 18, 1953 w. A. STEWART HYDRAULIC REMOTE-CONTROL SYSTEM 3 Sheets-Sheet 2 Filed May 23, 1951 III/IIllIIlllI/IIIII 1953 w. A. STEWART HYDRAULIC REMOTE-CONTROL SYSTEM 3 Sheets-Sheet 3 Filed May 25, 1951 .7510! rmc. A/gLnfd. flag :rus reeuner zfik, v

Patented Aug. 18, 1953 UNITED STATS TENT OFFICE Application May 23, 1951, Serial No. 227,810 In Great Britain April 27, 1950 7 Claims.

This invention relates to hydraulic remote control systems, for eiiecting movement of an object by means of a control device situated remotely from said object.

A hydraulic remote control system for controlling the throttle of an engine which latter is arranged to drive an output shaft in a forward direction through an ahead clutch and in a reverse direction through a reverse clutch, the throttle being displaceable from an engine idling position to positions where the engine speed is increased, said system comprising a hydraulic resistance having an inlet and an outlet, a con nection from said inlet to a source of hydraulic liquid under pressure, an assembly having a first principal part consisting of a cylinder and a second principal part consisting of a piston which latter is relatively axially movable in the cylinder in accordance with the pressure or the hydraulic liquid on said piston, a connection between one of the two parts of said assembly and the throttle of the engine, the connection holding the throttle in the idling position when the hydraulic pressure on the piston is below a predetermined value, means holding the other part of said assembly stationary, a first conduit for delivering hydraulic liquid from the outlet of the hydraulic resistance to said cylinder, a leak-off conduit communicating with said first conduit, a control valve for varying the rate of flow of hydraulic liquid along said leak-off conduit, the control valve having an unrestricted outlet, andthe control valve having an initial position in which the throttle is maintained in a position corresponding to an idling speed of the engine, and having driving positions in which for increased displacement of the control valve from its initial position, the valve progressively reduces the rate of flow of hydraulic liquid along said leak-off pipe, whereby the throttle is moved to increase the engine speed, a selector having three operative positions, connections between the selector and the clutches ensuring that in the first position of the selector the ahead clutch is engaged, in the second position of the selector neither clutch is engaged and in the third position of the selector the reverse clutch is engaged, and a single control means for operating the control valve and the selector, the

control valve being in its initial position when the selector is in its second position and being moved to driving positions when the selector is in its first and third positions.

For a better understanding of the invention and the manner of carrying it into eifect reference will now be made to the accompanying drawings in which;

Figure 1 is a diagrammatic representation of a hydraulic remote control system,

Figure 2 is a semi-diagrammatic representation of another hydraulic remote control system,

Figure 3 is a cross-sectional elevation on line IIIIII of the valve of the system of Figure 2,

Figure 4 is a section on line IV--IV of Figure 3,

Figure 5 is a section on line V-V of Figure 3, and

Figure 6 is a section on line VI-VI of Figure 3.

The remote control system shown in Figure 1 has a hydraulic pump I (which may be already provided for some other purpose 99), the delivery side 2 of which communicates via a pipe 3 with the inlet 4 of a hydraulic resistance 5. The outlet 6 of the hydraulic resistance 5 is connected by a pipe 1 to one end of an actuator 8. This actuator 8 consists of a cylinder 9 having a piston Ill therein, which latter is mechanically connected, by means of a piston rod II to the object (not shown) which it is desired to control. Flow of hydraulic fluid into the cylinder 9 causes the piston I0 to be moved translationally against the action of a spring I2 which is located within the cylinder 9.

A leak-off pipe I3 is connected to the pipe 1 and leads to the inlet I4 of a control valve I5, the outlet I6 from which communicates with a sump IT. The suction side I8 of the hydraulic pump I is connected to the sump I1.

The valve I5 has a handle I9 for controlling the leak-off of hydraulic fluid along the pipe I3.

The system described above operates in the following manner. The handle I9 is adjusted to the position A in which the valve I5 permits the maximum flow of the hydraulic fluid therethrough. Under these circumstances the maximum amount of hydraulic fluid, for a given pressure at the outlet 6 of the hydraulic resistance 5, leaks-01f through pipe I3 and the control valve I5. The pressure of fluid on the piston I0 of the actuator 8 is therefore at a minimum, and the spring I2 urges the piston I 0 to the fullest extent towards the left (Fig. 1) i, e. to the position A. When the control handle i9 is moved to reduce the flow of the hydraulic fluid through the valve I5, the rate of fluid leak-off is reduced and the pressure on the piston I0 is increased. The piston It) therefore moves against the spring I2 until the force on the piston [0 due to the new pressure is balanced by the force on the piston ID in the opposite direction clue to the spring I2. The piston rod I I rnoves with the piston I0 and causes the controlled object to be moved correspondingly. By correctly relating the cross-sectional area of the valve port (not shown) to the hydraulic resistance and the viscosity of the fluid, the position of the piston rod H can be made to alter corresponding to the displacement of the handle I9 until the valve i is shut when the spring 12 is just fully compressed and there is no leak-oil. The handle 19 will then be in position B and the piston in the position B.

When the control handle 19 is moved to increase leak-ofi', the pressure in the actuator cylinder 9 drops rapidly, and the piston rod Ii therefore rapidly follows the movement of the control handle l9. When however, the control handle [9 is moved in the opposite direction to reduce leak-01f, the pressure does not suddenly increase, on account of the action of the hydraulic resistance 5. There is therefore in this case a slight delay in the movement of the piston rod II in response to movement of the control handle I9.

The system described above is arranged to control, remotely, the throttle of an oil engine of a marine craft.

In this arrangement (Fig. 2) the oil engine 26 drives the propeller shaft (not shown) through either an ahead or an astern clutch (also not shown) in the gear box 2|, and the handle 22 of the throttle control valve also operates a hydraulic selector valve for connecting the engine to the propeller shaft through either the ahead or astern clutches.

The handle 22 is operated remotely through the intermediary of a hydraulic system 26 from a main control handle 23 located on the bridge of the marine craft. The handle 22 moves in correspondence with the handle 23. The throttle 25 of the engine 29 is connected by a rod 26 to the piston 21 of an actuator 28. The cylinder 29 of the actuator 28 is connected by a pipe 36 to a valve body 3!. Any hydraulic liquid leaking past the piston 2'! drains into the gear box sump 10! via a pipe [00. Hydraulic liquid under pressure is fed from a pump I02 in the gear box 2! through a pipe 32 to the body 3| of the control valve.

The pipe 32 is secured to the valve body 3| by a union 33 (Fig. 3). The pipe 32 communicates via a passageway 34, to port 35, a gauze filter 36 and a port 3'! with the inlet 38 of a rotor 39. The rotor 39 is rotatably mounted in the valve body 3! and the handle 22 is secured to the left-hand end (Fig. 3) of the rotor. The rotor 39 has a passageway 66 extending axially therethrough. A spring A! is located in the passageway 40, one end of the spring abutting against a plug 42 screwed into the rotor and the other end of the spring urging a plug 43 towards a pin 44 fixed to the valve body 3|.

The valve body 3! has a port 45 which leads to a passageway 46 in which a hydraulic resistance assembly 41 is located. The resistance assembly 41 has a cylindrical body 48 having a hole 49 longitudinally therethrough. An annular groove 56 is formed on the outside of the body 48 and ports 5! permit communication between the groove 50 and the interior of the body 48. A plunger 52 having a needle 53 is screwed into the body 48, there being an oil seal 54 for preventing leakage of hydraulic liquid between the body 48 and the plunger 52. A narrow inwardly directed rib 55 is formed on the inside of the body 48, the tapered point of the needle 53 passing through the circular orifice formed by the rib 55.

A hole 16 in the valve body 31 leads from the 4 location of the annular groove 56 to the pipe 39 (Fig. 4).

A port 56 (Fig. 4) in the valve body 31 communicates with the annular groove 56 and leads to the chamber 5'! in which the rotor 39 is located. The rotor 39 has a groove 58 (Figs. 3 and 4) for co-operating with the port 56. Two tapered V-sectioned grooves 59 and 66 are formed one on either side of the groove 58. These grooves 59 and 60 are largest where they communicate with the groove 58.

The rotor 39 has an annular groove 6! (Fig. 3) with which the groove 58 communicates. A port 62 leads from the groove 6! to the sump of the gear box 2|.

The rotor 39 has two ports 63, 64 (Fig. 5) for cooperating with the port 45, and these ports 63, 64 lead from the passageway 60 to the periphery of the rotor.

The rotor 39 has a port 65 (Fig. 6) for delivering hydraulic liquid from the passageway 46 either to a port 66 leading to the astern clutch of the gear box 2! or to a port 6'! leading to the body 3|, by the pipe 32.

ahead clutch of the gear box 2!.

A relief valve 68 (Fig. 3) is provided in a passageway 69 in the valve body 3| for enabling hydraulic fluid to by-pass the oil filter 36 if the latter becomes clogged.

The control valve operates as follows. With the handle 22 in the neutral position the rotor is in the position shown in Figs. 3-6. Hydraulic liquid under pressure is delivered to the valve The liquid passes through port 35, filter 36 and port 31 to the passageway 46 where it encounters the plug 63. The plug is deflected against the pressure of the spring 4| and uncovers the ports 63 and 64. In the neutral position the ports 63, 64 cannot cornmunicate with the port 45 and no fluid is delivered to the hydraulic resistance assembly 41. Furthermore, the port 65 cannot communicate with either of the ports 66, Bl and no liquid is delivered to the gear box for operating the clutches, hence no drive is transmitted from the engine 29 to the propeller shaft.

When the control handle 22 is moved to cause the craft to go ahead the port 65 communicates with the port 61 whereby engagement of the ahead clutch is effected. Next, the port 63 communicates with the port 45 and liquid flows to the resistance assembly 41. The flow of the liquid is restricted as it passes between the rib 55 and the needle 53. The liquid after passing the restriction flows through the ports 5! and some passes by way of hole 16 to the actuator 28 and the remainder passes through the port 56 and groove 56 to the groove 6! from whence it flows via port 62 to the gear box sump. The leak-off of liquid through the port 56 and groove 58 is relatively unrestricted until the handle has been turned far enough to bring the groove 58 out of register with the port 56. Until the latter takes place the pressure build-up in the pipe 30 is insuflicient to cause displacement of the piston 21 in the cylinder 29 and hence no movement of the throttle 25 takes place. When, however, the handle is turned far enough to cause the V groove 59 to register with the port 56 the liquid leak-off is restricted and pressure builds up in the pipe 36 causing displacement of the piston against spring pressure and hence movement of the throttle 25 to increase the speed of the engine. The oil pressure in the hole 10, pipe 30 and cylinder 29 builds up at a slower rate than the rate of movement of the 5, handle 22 on account of the restricting action of the hydraulic resistance.- Increased movement of the handle further restricts leak-oft since narrower portions of the groove 59 register with the port 56. Hence the pressure build-up in the pipe 30 is greater and the movement of the throttle 25 is greater. When the handle 22 reaches the full ahead position leak-off is prevented by the rotor 39 blanking-off the port 56.

When the handle 22 is moved from the full ahead position towards the neutral position the pressure in this pipe 30 drops without a time delay since liquid can leak-on relatively freely through the groove 58 without having to pass through the restriction formed by the rib t and the needle 53.

When the handle 22 is moved to cause the craft to go astern the port 65 registers with the port 66 whereby the astern clutch is engaged, the port 64 registers with the port E5, and the V -groo ve 6U eventually registers with the port 5 6. The operation is otherwise similar to that described for going ahead.

It will be seen therefore, that when the control handle 22 is moved to increase the engine speed, the throttle 25 lags on account of the action of the hydraulic resistance. If therefore the handle 22 is moved too quickly from the central, or neutral" position to either the full ahead or "full astern position, the engine speed will only increase relatively slowly at a predetermined rate. In the reverse directions of movement of the control handle 22, however, the pressure drop is rapid and the throttle 25 follows immediately the movements of the handle.

It is to be understood that if desired the ports in the rotor 39 could be so arranged that when the control handle 22 is moved to ahead positions, slight movement of the throttle 25 is effected to increase the speed of the engine before the ahead clutch is engaged. Similarly, when the control handle 22 is moved to astern positions, the throttle 25 could again be moved a slight amount to increase the speed of the engine before the astern clutch is engaged.

I claim:

1. A hydraulic remote control system for controlling the throttle of an engine which latter is arranged to drive an output shaft in a forward direction through an ahead clutch and in a reverse direction through a reverse clutch, the throttle being displaceable from an engine idling position to positions where the engine speed is increased, said system comprising a hydraulic resistance having an inlet and an outlet, a connection from said inlet to a source of hydraulic liquid under pressure, an assembly having a first principal part consisting of a cylinder and a second principal part consisting of a piston which latter is relatively axially movable in the cylinder in accordance with the pressure of the hydraulic liquid on said piston, a connection between one of the two parts of said assembly and the throttle of the engine, the connection holding the throttle in the idling position when the hydraulic pressure on the piston is below a predetermined value, means holding the other part of said assembly stationary, a first conduit for delivering hydraulic liquid from the outlet of the hydraulic resistance to said cylinder, at leak-off conduit communicating with said first conduit, a control valve for varying the rate of flow of hydraulic liquid along said leak-01f conduit, the control valve having an unrestricted outlet, and the control valve having an initial position in which: the throttle is maintained in. a position corresponding to an idling speed of the engine, and having driving positions in which for increased displacement of the control. valve from its initial position, the valve progressively reduces the rate of flow of hydraulic liquid along said leak-off pipe, whereby the throttle is moved to increase the engine speed, a selector having three operative positions, connections between the selector and the clutches ensuring that in the first position or? the selector the ahead clutch is engaged, in the second position of the selector neither clutch is engaged and in the third position of the selector the reverse clutch is engaged, and a single control means for operating the control valve and the selector, the control valve being in its initial position when the selector is in its second position and being moved to driving post-ions when the selector is in its first and third positions.

2'. A system according to claim 1 and further comprising a master valve for preventing flow of liquid from said source to said hydraulic resistance when said control valve is in its initial position, and connections between the master valve and said means for operating the control valve and the selector, whereby this means serves also for operating the master valve.

3. A system as claimed in claim 1, and further comprising a sump, a conduit for leading the liquid leaking-off through the control valve into the sump, a pump constituting said source of hydraulic liquid under pressure, and a pipe leading from the sump to the inlet of the pump.

4. A system according to claim 1, wherein the resistance comprises an adjustably fixed tapered needle which is passed through a constriction in the flow path of the hydraulic liquid.

5. A system according to claim 4, wherein the constriction is narrow as measured along the flow path of the hydraulic liquid.

6. A hydraulic remote control system for controlling the throttle of an engine which latter is arranged to drive an output shaft in a forward direction through a hydraulically operated ahead clutch and in a reverse direction through a hydraulically operated reverse clutch the throttle being displaceable from an engine idling position to positions where the engine speed is increased, said system comprising a. hydraulic resistance having an inlet and an outlet, a connection from said inlet to a source of hydraulic liquid under pressure, an assembly having a first principal part consisting of a, cylinder and a second principal part consisting of a piston which latter is relatively axially movable in the cylinder in accordance with the pressure of the hydraulic liquid acting on said piston, a connection between one of the two parts of said assembly and the throttle of the engine, the connection holding the throttle in the idling position when the hydraulic pressure on the piston is below a predetermined value, means holding the other part of said assembly stationary, a first conduit for delivering hydraulic liquid from the outlet of the hydraulic resistance to said cylinder, a leak-01f conduit communicating with said first conduit, a control valve for varying the rate of flow of hydraulic liquid along said leak-oil conduit, the control valve having an unrestricted outlet, and the control valve having an initial position in which the throttle is maintained in a position corresponding to an idling speed of the engine and having driving positions in which for increased displacement of the valve from its initial position, the valve progressively reduces the rate of flow of liquid along said leak-ofi pipe, whereby the throttle is moved to increase the engine speed, a hydraulic selector valve having three operative positions, a second conduit between the selector valve and the ahead clutch for delivering liquid to the ahead clutch to cause engagement thereof when the selector valve is in the first position, a third conduit between the selector valve and the reverse clutch for delivering liquid to the reverse clutch to cause engagement thereof when the selector valve is in the third position, the selector valve being closed when in the second position, and a single control means for operating the control valve and the hydraulic selector valve, the control valve being in its initial position when the selector valve is in its second position and being moved to driving positions when the selector valve is in its first and third positions.

7. A system according to claim 6, and further comprising a valve body, and a valve rotor rotatably mounted in said valve body, wherein the selector valve and the control valve are formed in said valve rotor, and wherein the means for operating the selector valve and the control valve is a single control handle for rotating the rotor.

WALTER AUGUSTUS STEWART.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,005,731 Ernst June 25, 1935 2,227,174 Boster Dec. 31, 1940 2,372,393 Ray Mar. 27, 1945 2,386,392 Fike Oct. 9, 1945 2,432,502 Bentley Dec. 16, 1947 2,446,329 I-Iieger Aug. 3, 1948 FOREIGN PATENTS Number Country Date 474,539 Great Britain Nov. 3, 1937 475,693 Great Britain 1 Nov. 24, 1937 

